linux-kernel - RE: [PATCH 5/5] hv: Track allocations of children of hv

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Message-ID: <BY2PR0301MB16542F997FB348465274DC4BA0B80@BY2PR0301MB1654.namprd03.prod.outlook.com>
Date:	Sat, 27 Feb 2016 01:09:11 +0000
From:	KY Srinivasan <kys@...rosoft.com>
To:	Jake Oshins <jakeo@...rosoft.com>,
	"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
	"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"devel@...uxdriverproject.org" <devel@...uxdriverproject.org>,
	"olaf@...fle.de" <olaf@...fle.de>,
	"apw@...onical.com" <apw@...onical.com>,
	"vkuznets@...hat.com" <vkuznets@...hat.com>,
	Haiyang Zhang <haiyangz@...rosoft.com>,
	Hadden Hoppert <haddenh@...rosoft.com>
CC:	Jake Oshins <jakeo@...rosoft.com>
Subject: RE: [PATCH 5/5] hv: Track allocations of children of hv_vmbus in
 private resource tree



> -----Original Message-----
> From: jakeo@...rosoft.com [mailto:jakeo@...rosoft.com]
> Sent: Wednesday, February 24, 2016 1:24 PM
> To: linux-pci@...r.kernel.org; gregkh@...uxfoundation.org; KY Srinivasan
> <kys@...rosoft.com>; linux-kernel@...r.kernel.org;
> devel@...uxdriverproject.org; olaf@...fle.de; apw@...onical.com;
> vkuznets@...hat.com; Haiyang Zhang <haiyangz@...rosoft.com>; Hadden
> Hoppert <haddenh@...rosoft.com>
> Cc: Jake Oshins <jakeo@...rosoft.com>
> Subject: [PATCH 5/5] hv: Track allocations of children of hv_vmbus in private
> resource tree
> 
> From: Jake Oshins <jakeo@...rosoft.com>
> 
> This patch changes vmbus_allocate_mmio() and vmbus_free_mmio() so
> that when child paravirtual devices allocate memory-mapped I/O
> space, they allocate it privately from a resource tree pointed
> at by hyperv_mmio and also by the public resource tree
> iomem_resource.  This allows the region to be marked as "busy"
> in the private tree, but a "bridge window" in the public tree,
> guaranteeing that no two bridge windows will overlap each other
> but while also allowing the PCI device children of the bridge
> windows to overlap that window.
> 
> One might conclude that this belongs in the pnp layer, rather
> than in this driver.  Rafael Wysocki, the maintainter of the
> pnp layer, has previously asked that we not modify the pnp layer
> as it is considered deprecated.  This patch is thus essentially
> a workaround.
> 
> Signed-off-by: Jake Oshins <jakeo@...rosoft.com>
> ---
>  drivers/hv/vmbus_drv.c | 22 +++++++++++++++++++++-
>  1 file changed, 21 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
> index b090548..2a7eb3f 100644
> --- a/drivers/hv/vmbus_drv.c
> +++ b/drivers/hv/vmbus_drv.c
> @@ -1169,7 +1169,7 @@ int vmbus_allocate_mmio(struct resource **new,
> struct hv_device *device_obj,
>  			resource_size_t size, resource_size_t align,
>  			bool fb_overlap_ok)
>  {
> -	struct resource *iter;
> +	struct resource *iter, *shadow;
>  	resource_size_t range_min, range_max, start, local_min, local_max;
>  	const char *dev_n = dev_name(&device_obj->device);
>  	u32 fb_end = screen_info.lfb_base + (screen_info.lfb_size << 1);
> @@ -1211,12 +1211,22 @@ int vmbus_allocate_mmio(struct resource
> **new, struct hv_device *device_obj,
> 
>  			start = (local_min + align - 1) & ~(align - 1);
>  			for (; start + size - 1 <= local_max; start += align) {
> +				shadow = __request_region(iter, start,
> +							  size,
> +							  NULL,
> +							  IORESOURCE_BUSY);
> +				if (!shadow)
> +					continue;
> +
>  				*new =
> request_mem_region_exclusive(start, size,
>  								    dev_n);
>  				if (*new) {
> +					shadow->name = (char*)*new;

Why are you not correctly setting the name field in the shadow structure?

Regards,

K. Y